Derivatives of dinorcholestane and process

ABSTRACT

A PROCESS FOR THE PREPARATION OF LOWR ALKYL ESTERS OF 26,27-DINORCHLOESTEN-25-OIC ACIDS OF THE FORMULA I   7,8-A,20-(R-OOC-(CH2)3-)PREGN-5-EN-3-OL   WHEREIN R IS LOWER ALKYL AND A IS TWO HYDROGENS OR A DOUBLE BOND AND INTERMEDIATES SO PRODUCED. THE COMPOUNDS OF THE FORMULA I ARE INTERMEDIATES IN THE SYNTHESIS OF 25-HYDROXY CHLOESTEROL AND 25-HYDROXY-7(8)DEHYDRO-CHOLESTEROL. THESE LATTER COMPOUNDS ARE THEMSELVES INTERMEDIATES IN THE PREPARATION OF 25-HYDROXYCHOLECALCIFEROL WHICH POSSESSES AN IMPORTANT ANTI-RACHITIC PROPERTY, SUPERIOR TO THAT OF CHOLECALCIFEROL OR VITAMIN D3,

B. GOFFINET 3,801,607

DERIVATIVES 0F DINORCHOLESTANE AND PROCESS April 2, 1974 Filed March 10,1972 moou United States Patent 3,801,607 DERIVATIVES 0F DINORCHOLESTANEAND PROCESS Bernard Goliinet, Paris, France, assignor to Roussel-UCLAF,Paris, France Filed Mar. 10, 1972, Ser. No. 233,767 Claims priority,application France, Mar. 11, 1971,

Im. 01. C07c 169/52 US. Cl. 260-3971 21 Claims ABSTRACT OF THEDISCLOSURE A process for the preparation of lower alkyl esters of26,27-dinorcholesten-25-oic acids of the Formula I A OOR THE PRIOR ART25-hydroxy-cholesterol has been prepared up to the present by a Grignardreaction on norcholestenolone (3B- hydroxy-Z-oxo-27-nor-cholest-5-ene),as described by Ryer et al., J. Am. Chem. Soc. 72, 4247 (1950).

Norcholestenolone is one of the by-products of the oxidation ofdibromocholesterol acetate by chromic acid. It is known that thisoxidation reaction leads, with very low yields after difficultisolations and purifications, to numerous products, namely,androstenolone, pregnenolone, norcholestenolone,3fl-hydroxy-chol-5-en-24-oic acid, etc., as described, for example byRuzicka et al., Helv. Chim. Acta, 20, 1291 (1937) and Butenandt et al.,Z. Physiol. Chem. 237, 57 (1935).

This oxidation reaction of dibromocholesterol has been formerly utilizedindustrially in order principally to prepare androstenolone which is akey compound allowing access to the principal sex hormones. However,since the development of new processes using starting materials ofvegetable origin (sapogenines) which are more readily converted intoandrostenolone, the reaction of the degradation of cholesterol is nolonger utilized in industry.

This results that norcholestenolone is not actually a satisfactorystarting material for the industrial synthesis of25-hydroxy-cholesterol. More recently, 25-hydroxycholesterol has beenprepared by a Grignard reaction on an ester of 3 3-hydroxy26,27-dinor-cholest-5-en-25-oic acid [Campbell et al., Steroids, 13,567-577 (1969)]. This latter acid was obtained by homologation of3B-hydroxy-chol-S-en-oic acid according to an Arndt-Eistert reaction;see Dauben, J. Am. Chem. Soc. 74, 599 (1952).

However, Bfl-hydroxy-chol-5-en-24-oic acid is one of the products of thedegradation reaction of cholesterol, as indicated above. For the samereasons as those above, this cholenoic acid is not presently asatisfactory starting material for the industrial synthesis of25-hydroxycholesterol.

3,801,607 Patented Apr. 2, 1974 ice3p-hydroxy-26,27-dinorcholest-5-en-25-oic acid has also been obtained bycleavage of norcholestenolone by means of an oxidizing agent (FrenchPat. No. 1,334,932). It is evident from the above, that this reactionalso presents 5 no interest for the synthesis of 25-hydroxy-cholesterol.

OBJECTS OF THE INVENTION An object of the present invention is a processfor the production of dinorcholestane derivatives useful in theproduction of compounds having anti-rachitic properties.

A further object of the invention is the development of a process forthe preparation of esters of 26,27-dinorcholestadien-ZS-oic acid of theformula COOH wherein R represents the acyl of an organic carboxylic acidhaving 1 to 10 carbon atoms and R represents lower alkyl, which consistsessentially of the steps of (a) Subjecting a compound of the formulaRio-- wherein R represents the acyl of an organic carboxylic i i i 13H=Owherein R, has the above assigned meaning,

(0) Subjecting the result-ant compound of the formula GOOR 3 wherein Rrepresents lower alkyl, to a catalytic hydrogenation,

(d) Oxidizing the resultant compound of the formula coon 110-- I whereinR has the above-assigned meaning, by the action of an oxidizing agentcapable of oxidizing a hydroxy to 'a ketone,

(e) Brominating the resultant compound of the formula wherein R has theabove-assigned meaning, by the action of a monobrominating agent,

(if) Reacting the resultant compound of the formula COOR O E Br whereinR has the above assigned meaning, with a dehydrobrominating agent,

(g) Reacting the resultant compound of the formula .COOR

wherein R has the above-assigned meaning, with an acyl'ating derivativeof an organic carboxylic acid having 1 to 10 carbon atoms, and

(h) Recovering said esters of 26,27-dinorcholestadien- 25-oic acid.

A yet further object of the invention is the obtention of the novelintermediates (2.) A compound of the formula CO0R| Rao" wherein R is amember selected from the group consisting of hydrogen and the acyl of anorganic carboxylic acid having 1 to 10 carbon atoms and R is a memberzclellecited from the group consisting of hydrogen and lower 4 (b) Acompound of the formula wherein R is lower alkyl, X is a 53 hydrogen andX is a member selected from the group consisting of hydrogen andbromine.

'(c) A compound of the formula ft W CODE

wherein R is lower alkyl and A is a member selected from the groupconsisting of two hydrogens and a double bond.

(d) A compound of the formula W OO O...

i Br wherein R is lower alkyl, and

(f) A compound of the formula 00R HO wherein R is lower alkyl.

These and other objects of the invention will become more apparent asthe description thereof proceeds.

THE DRAWING The figure is a schematic flow diagram of the process-DESCRIPTION The present invention relates to a process for thepreparation of lower alkyl esters of 26,27-dinorcholesten-25- oic acidsof the Formula I wherein R is lower alkyl and A is two hydrogens or adouble bond and intermediates so produced. The com- 0 pounds of theFormula I are intermediates in the synthesis of -hydroxycholesterol and25-hydroxy-7(8)-dehydro-cholesterol. These latter compounds arethemselves intermediates in the preparation ofZS-hydroxy-cholecalciferol which possesses an important anti-rachiticproperty, 25 superior to that of cholecalciferol or vitamin D [see, forexample, Campbell et al., Steroids, 13, 567-577 (1969)].

This process of the invention is represented schematically on thedrawing. For consistency hereafter, the letter a will be used forFormulas VIII, IX and I where they designate unsaturated compoundshaving a double bond in position 4(5) in Formula VIII and in position5(6) in Formulas IX and I, and the letter b will be used in formulas todesignate unsaturated compoundshaving the double bond system A inFormula VIII and A in Formulas IX and I.

It will be noted that the products of Formula Ib can be transformed into25-hydroxy-cholecalciferol, either by a Grignard reaction thenirradiation-isomerization, or, by reversing the order of the reactions,by irradiationisomerization then the Grignard reaction. These twomethods of preparation are described in the article by Campbell et al.,cited above, and the published French patent application No. 2,012,069.

The present invention rests particularly in the discovery of a newprocess of synthesis of 3p-hydroxy-26,27- dinorcholest-S-en-ZS-oic acidstarting from products of transformation of lithocholic acid. Thisprocess consists principally of transforming a derivative of lithocholicacid into its higher homolog, then introducing a double bond in the 5position. These operations are effected according to methods known perse.

The advantage of the new synthesis of the invention resides principallyin the choice of a starting material easily obtainable in view ofindustrial utilization. In fact, lithocholic acid is, along with cholicacid and desoxycholic acid, one of the three principal bile acidsisolated from the bile of cattle.

Lithocholic acid can also be prepared starting from other bile acids,such as cholic acid, desoxycholic acid, hyodesoxycholic acid; see Fieserand Fieser, Steroids, Reinhold Publishing Corp., New York (1959), pages77-,

81 and French Pat. No. 1,418,446.

Another advantage of the process of the invention is that it leads tointermediates which permit, if desired, the introduction of asupplementary double bond in the 7(8) position. According to thisvariant of the process, a derivative of dinorcholesta-5,7-dienoic acidis obtained, which by a Grignard reaction is transformable into 7(8)-dehydro-2S-hydroxy-cholesterol. This dinorcholestadienoic acid wasobtained by Campbell et al., cited supra, by allylic bromination anddehydrobromination of the corresponding dinorcholest-S-enoic acid.However, this reaction of allylic bromination leads to irregular resultsand to only low yields.

The present invention is concerned in the first place to the particularstep of the preparation of the compounds of Formula I.

uAccording to the invention, the compounds of the Form a I A COORwherein R is lower alkyl, such as methyl, and A is selected from thegroup consisting of two hydrogens and a double bond, are prepared by aprocess characterized by reacting a compound of the Formula V111 whereinR and A have the above-assigned meanings, with an acylation agent inorder to form a compound of the Formula IX wherein R and A have theabove-assigned meanings and R represents the acyl of an organiccarboxylic acid, reducing the 3(4) double bond in this latter compoundby a mixed hydride and isolating the desired compound of Formula I.

In the above-described process, as 'well as hereafter, the substituent Ris lower alkyl, preferably of 1 to 6 carbon atoms, such as methyl,ethyl, n-propyl, isopropyl, etc. Also the substituent R is the acyl ofan organic carboxylic acid having preferably from 1 to 10 carbon atoms.R represents particularly the acyl of a saturated or unsaturated,aliphatic or cycloaliphatic acid, and especially an alkanoic acid havingfrom 1 to 10 carbon atoms, such as formic acid, acetic acid, propionicacid, butyric acid, isobutyric acid; a cycloalkylcarboxylic acid or acycloalkylalkanoic acid having from 4 to 10 carbon atoms, such ascyclopropyl-, cylopentylor cyclohexylcarboxylic acid, ylopentyloryclohexyl-acetic or propionic acids; an arylcarboxylic acid,particularly benzoic acid or an al-kylbenzoic acid having from 8 to 10carbon atoms, such as toluenic acid; or an aryl-alkanoic acid,particularly a phenylalkanoic acid or an alkylphenylalkanoic acid havingfrom 8 to 10 carbon atoms, such as phenyl-acetic or propionic acid.

In order to prepare, according to this process, a compound of theFormula Ia COOR a compound of the Formula VIIIa of l (VIIIa) is reactedwith an acylation agent in order to form a compound of the FormulaIXaCOOR C OR

is prepared by reacting a compound of the Formula VIIIb CODE (VIIIb)with an acylation agent in order to form a compound of the Formula IXb HdooR wherein R and R have the above-assigned meanings, and the latterCompound IXb is subjected to the action of a mixed hydride.

The invention also is directed to a process such as defined above, wherea product of the Formula VIIIa is prepared by subjecting a compound ofthe Formula VI where R is lower alkyl, to the action of an oxidizingagent in order to form a compound of the Formula VII and the double bondin the 4(5) position is introduced according to known methods.

The invention is also directed to a process such as defined above, wherea compound of the Formula VIIIb is prepared by introducing a double bondin the 6(7) position of a compound of Formula VIIIa according to knownmethods. The compound of the Formula VIIIb is next transformed into acompound of Formula Ib according to the methods described above.

A compound of Formula VIIIb can also be prepared by subjecting acompound of the Formula Ia to the action of a dehydrogenating agentselected from the group consisting of a quinone in the presence of analuminum alcoholate, or manganese dioxide. The compound of Formula VIIIbis then transformed into a compound of Formula Ib as described above.

In order to prepare, also according to the invention, the compounds ofFormula VT wherein R represents the acyl of an organic carboxylic acidand X represents a lower alkyl, a cycloalkyl or an aryl, is subjected tothe action of ozone. The ozonide formed is subjected to the action of areducing agent in order to give a compound of the Formula IV This lattercompound is transformed by a Wittig reaction into a compound of theFormula V O 0 OR wherein R and R have the above-assigned meanings, and

the latter compound is subjected to a catalytic hydrogenation to give acompound of Formula VI.

In the above-described process, when X represents a lower alkyl, it ispreferably an alkyl having from 1 to 6 carbon atoms; when X representscycloalkyl, it is preferably a cycloalkyl having from 5 to 6 carbonatoms; and when X represents aryl (such as phenyl), it is preferably anaryl having from 6 to 10 carbon atoms.

The compound of Formula III, utilized as starting compounds in theprocess of the invention, are either known or easily obtained startingfrom lithocholic acid by application of known methods; see, for example,Meystre et al., Helv. Chim. Acta 29, 33 (1946).

The compounds of Formula VI can also be prepared by the Arndt-Eistertreaction. According to this reaction,

a compound of the Formula II lilo-L in which R has the above-assignedmeaning, is subjected to the action of diazomethane to form a compoundof the formula (WV /U H which is decomposed by the action of water or alower alkanol of the Formula ROH, in the presence of a metalliccatalyst, particularly a catalyst based on silver, in order to form acompound of the Formula VI wherein R has the above-assigned meaning andR represents hydrogen or lower alkyl (R). This latter compound issaponified by the action of an alkaline base in order to form a compoundof the formula which is esterified on the carboxyl group with a loweralkanol according to known methods to give a compound of the Formula VI.

The acid chlorides of the compound of Formula II, utilized as startingmaterials in the above process are either known or easily obtainedstarting from lithocholic acid by application of known methods; see, forexample, I. Am. Chem. Soc. 67, 740 (1945).

Some other characteristics of these processes, as well as the preferredmethods of execution, are described here below.

10 (a) Ozonization, passage of Compound III to Compound IV This reactionis effected by bubbling a stream of ozonized oxygen through a solventsolution of Compound III, in a solvent which is inert under the reactionconditions such as methylene chloride, chloroform, carbon tetrachlorideor ethyl acetate. The reaction is conducted at temperatures below 0 C.and preferably from 75 C. to 50 0., especially about 60 C.

The reducing agent utilized to reduce the ozonide formed is preferablyzinc in the presence of acetic acid. -Also, however, a lower alkylphosphite, such as trimethyl phosphite, or a dialkyl sulfide, such asdimethyl sulfide, can be utilized. The reaction is conducted in thesolvent solution of the ozonide obtained as above at reducedtemperatures of from 75 C. to +10 C. The desired product of Compound IVis preferably isolated by formation of its 23-oxo ketal, such as thedimethyl ketal and subsequent acidic hydrolysis.

(b) Wittig reaction, passage of Compound IV to Compound V For thisreaction, particularly a lower alkyl 0,0-lower alkylphosphonoacetate isutilized having the formula lower alkyl-O\ /PCH2 C O O R lower alkyl-O Ofor example methyl 0,0-diethylphosphonoacetate, in the presence of astrong base. An alkylidene phosphorane of the formula Ar-P=CHC 0 O R inwhich Ar is aryl, such as phenyl and R is lower alkyl, may also beutilized in the Wittig reaction.

The reaction is eifected under the usual conditions employed in Wittigreactions. The strong base utilized in the case of the use of thephosphonoacetates is particularly an alkali metal alcoholate, especiallyan alkali metal lower alkanolate, such as sodium methylate or sodiumethylate; an akali metal hydride or an alkali metal amide.

The reaction is effected in a lower alkanol (in the presence of itsalkali metal alcoholate), or also in an ether (such as diethyl ether,tetrahydrofuran, etc.) an amide (such as dimethylformamide), or ahydrocarbon, (such as benzene, toluene or cyclohexane).

The obtention of the ethyl ester of 3-hydroxy-26,27-dinorcholest-23-ene-25-oic acid (an intermediate in the synthesis ofcholestane-Z3,24,25-triol), by the action ofcarbethoxy-methylenetriphenylphosphorane on 3-hydroxy-23-oxo-24-nor-cholane is described in the published Japanese patentapplication No. 22,542/70. The 23-oxo derivative is obtained in thispatent by branching of the norcholanic chain on a pregnane derivative.

(c) Catalytic hydrogenation, passage of Compound V to Compound VI Thisreaction is effected by the action of hydrogen in the presence of acatalyst. Particularly a hydrogenation catalyst based on palladium,platinum or nickel is utilized.

(d) Oxidation reaction, passage of Compound VI to Compound VII Thecustomary oxidizing agents for the oxidation of secondary alcohols areemployed. In particular, a metallic oxide such as chromic anhydride, forexample the Jones reactant (chromic acid anhydride and sulfuric acid inan aqueous medium) is employed. Bromine in the presence of a butlerallowing neutralization of the hydrobromic acid formed, can also beemployed. In addition, an N-haloamide, such as N-bromoacetamide orN-bromosuccinimide can also be employed as an oxidizing agent, whileoperating, for example, in tertiary butanol or acetone, in the presenceof water or pyridine. The oxidizing agent can also be a ketone such ascyclohexanone in the presence of an aluminum alcoholate (Oppenauerreaction). The oxidation may also be conducted by means of cyclohexanonein the presence of Raney nickel.

(e) Introduction of a double bond in the 4 position, passage of CompoundVII to Compound VHIa wherein R is lower alkyl, is reacted with abromination agent in order to form a compound of the Formula X J COORwhich compound is subjected to a dehydrobromination reaction accordingto known methods.

The bromination agent employed is preferably bromine, the reaction beingconducted in the presence of hydrobromic acid in a dialkylamide such asdimethylformamide. However, other brominating agents such as an alkalimetal bromate, for example, potassium bromate, in an acid medium;perbromopyridine hydrobromide in the presence of an acid; orN-bromosuccinimide in an alcohol such as tertiary butanol or benzylalcohol; may be employed in the reaction.

A compound of Formula X is obtained where the bromine is in the 0a or[3-position.

Also a compound of the Formula X can be obtained directly by a reactionof a compound of the Formula VI with bromine in the presence of an acid.

The dehydrobromination of Compound X is effected according to knownmethods, for example by means of a lithium halide in a dialkylamide suchas dimethylformamide heated to reflux, preferably in the presence oflithium carbonate. The dehydrobromination can also be effected byheating Compound X in a pyridinic base, such as pyridine, collidine,picoline, lutidine, etc., or also by the action of a hydrazine, analkylhydrazine or a phenylhydrazine (for example,dinitrophenylhydrazine) or by the action of a semicarbazide, followed byan exchange reaction with a carbonylated derivative such asformaldehyde, glyoxal, glyoxylic acid, levulinic acid or pyruvic acid,in order to cleave the hydrazone or semicarbazone formed.

(f) Formation of the enolic ester, passage of Compound VIII to CompoundIX This reaction is an acylation reaction of the A -3-oxo compound. Theacylation agent is preferably the acid anhydride of the formula (R CO)O, where R has the above-assigned meaning, or a mixture of the anhydrideand of the corresponding acid chloride. The reaction is conducted eitherin the presence or in the absence of a tertiary base such as pyridine.In order to form the enolic ester of Compound VIIIb, the reaction ispreferably conducted in the presence of a tertiary base. For example,

in order to prepare the enolic acetate, a mixture of acetic acidanhydride and acetyl chloride is employed.

The enolic acetate can also be prepared by the action of isopropenylacetate in the presence of an acid catalyst such as, p-toluenesulfonicacid or sulfuric acid.

(g) Reduction of the enolic ester, passage of Compound IX to Compound IThe enolic ester of Compound IX is reduced by a mixed hydride. Thismixed hydride is preferably an alkali metal borohydride such aspotassium or sodium borohydride. The reducing agent can also be lithiumaluminum hydride or lithium tri-tert.-butoxy-aluminum hydride. The useof these reducing agents leads most often to a, at least partial,saponification of the ester group on the lateral chain. Generally,therefore, a mixture of the ester of Compound I and the correspondingfree acid are obtained.

In order to totally transform Compound IX into the ester of the compoundof Formula I, it is thus advantageous to submit the mixture obtainedafter the reduction to an esterification reaction according to the usualmethods, for example, by the action of a diazo-lower alkane or of thealcohol ROH in the presence of an acid catalyst such as hydrochloricacid, p-toluenesulfonic acid, or also acetyl chloride.

(h) Introduction of a double bond in the 6(7) position in Compound VIH,passage of Compound VIHa to Compound VIIIb In order to introduce thisdouble bond, according to the actually preferred method, Compound VIIIais reacted with an acylation agent in order to form a compound of theFormula IXa, in a method analogous to that described hereabove inparagraph (f). The Compound IXa is then subjected to the action of abromination agent in order to form a compound of the Formula XI and thislatter Compound XI is subject to a dehydrobromination in order to obtainCompound VHIb.

The bromination agent is preferably N-bromosuccinimide in the midst of amixture of dimethylformamide and water. Bromine can also be utilized asthe bromination agent, while operating, for example, in the presence ofa mixture of acetic acid and collidine.

Compound XI can also be obtained by direct bromination of Compound VIIIaby means of bromine in the presence of an acid.

In order to effect the dehydrobromination of Compound XI, the reactionis conducted by a lithium halide, such as lithium bromide, preferably inthe presence of lithium carbonate, in the midst of a dialkylamide suchas dimethylformamide.

The double bond in the 6(7) position can also be introduced whilepreparing intermediarily an enolic ether of Compound VIHa by the actionof an etheri-fication agent selected from the group consisting of anorthoformiate of a lower alkyl of the formula HC-OY 13 wherein Y is alower alkyl, such as ethyl orthoformiate, or a 2,2-dialkoxypropane ofthe formula CE: /OY C\ (II Ia O Y such as 2,2-dimethoxypropane. Thisenolic ether is a compound of the Formula XII COOR (XII) wherein R islower alkyl and Y is lower alkyl, having preferably from 1 to 4 carbonatoms, and is next transformed into Compound VI'IIb either bybromination followed by dehydrobromination, or directly by the action ofa dehydrogenating agent such as, for example,dichloro-dicyanobenzoquinone in an aqueous medium, for example, in thepresence of a mixture of acetone and water.

The bromination of the compound of Formula XII is eifected, for example,by the action of N-bromosuccinimide, and the dehydrobromination, by theaction of an alkali metal or alkaline earth metal carbonate indimethylformamide.

The introduction of the double bond allowing passage of Compound-Ulla toCompound VIIIb can also be effected directly by the action of adehydrogenating agent such as chloranil. This reaction is conducted, forexample, -by heating in the presence of tert. butanol or xylene.

(i) Passage of Compound Ia to Compound VIIIb (j) Preparation of CompoundVI according to the Arndt-Eistert reaction After the diazoketoneintermediate of Compound II is formed, it is decomposed in the presenceof a metallic catalyst. The metallic catalyst utilized is particularly acatalyst based on silver, copper or platinum. Preferably, a catalystbased on silver is utilized.

When the decomposition is elfected in the presence of water, for exampleby means of an aqueous suspension of silver oxide, the acid of FormulaVI is obtained, with R =H. When the decomposition is effected by meansof a lower alkanol R-OH, in the presence of silver oxide, or also in thepresence of an organic salt of silver in the presence of a tertiary base(for example, silver benzoate in the presence of triethylamine), anester of the Formula VI is obtained, with R =R.

In either case, the hydroxyl in the 3 position is liberated bysaponification by means of an alkaline base, such as aqueous sodium orpotassium hydroxide. The carboxylic group of the product obtained (VI',R =H) is then esterified according to usual methods, for example by theaction of a diazo-lower alkane, such as diazomethane diazoethane, or bythe action of a lower alkanol, ROH, in the presence of an acid catalyst.

The processes described above allow the obtaining of the following novelproducts.

(1) The compounds of Formula VIII, and particularly the methyl ester of3-oxo-26,27-dinorcholest-4-en-25-oic 14 acid, and the methyl ester of3-oxo-26,27-dinorcholesta- 4,6-dien-25-oic acid;

(2) The compounds of Formula VI COORI (VIII) CODE X: wherein R is loweralkyl, X is a hydrogen in the 5,3 position and X is hydrogen or bromine,and particularly the methyl ester of 3 oxo 26,27dinor-Sfi-cholestan-ZS-oic acid and the methyl ester of3-oxo-4-bromo-26,27-dinor- Sfl-cholestan-ZS-oic acid; this latterformula encompasses the compounds of Formulas VII and X;

(4) The compounds of Formula IX, and particularly the methyl ester of3-acetoxy-26,27-dinor-cholesta-3,5- dien-25-0ic acid and the methylester of 3-acetoxy-26,27- dinor-cholesta-3,5,7-trien-25-oic acid;

(5) The compounds of Formula XI, and particularly the methyl ester of3-oxo-6p-bromo-26,27-dinorcholest- 4-en-2S-oic acid;

(6) The compounds of Formula Ib, and particularly the methyl ester of 33-hydroxy-26,27-dinorcholesta-5,7-dien- 25-0ic acid;

(7) The compounds of Formula XII; as well as (8) The following products(a) 3a-acetoxy-23,23-dimethoxy-24-nor-Sfi-cholane, and (b) the methylester of 3a-hydroxy-26,27-dinor-23-trans- 5fl-cholest-23-en-25-oic acid.

The following examples illustrate the invention without, however,limiting the same in any respect.

EXAMPLE I Preparation of the methyl ester of 3,6-hydroxy-26,27-dinorcholest-S-en-ZS-oic acid Step A.3u-acetoxy 23oxo-24-nor-5fl-cholane: gm. of3ot-acetoxy-24,24-diphenyl-Sfi-chol-ZS-ene were dissolved in 800 cc. ofmethylene chloride. The solution was cooled to -60 C. and a stream ofozonized oxygen was bubbled therethrough for a period of 3 hours whilemaintaining this temperature. Then the dissolved oxygenated gas waseliminated by bubbling a stream of nitrogen therethrough. Thereafter,gm. of powdered zinc was added to the solution, and then 225 cc. ofacetic acid were added thereto. The temperature of the solution wasallowed to mount to 0 C. The excess zinc was separated by filtration.The filtrate was washed with a 5% aqueous solution of sodium bicarbonateand then evaporated to dryness under reduced pressure. The residueobtained comprises a mixture of 3a-acetoxy-23-oxo-24-nor-5 3- cholaneand benzophenone. The desired product was isolated in the form of thedimethylketal which was thereafter hydrolyzed. The method was thefollowing:

Ketalization: The residue obtained above was mixed with 300 cc. ofmethanol. Then 5 cc. of a 20% methanolic solution of acetyl chloride wasadded thereto. The mixture was agitated for a period of one hour atambient temperature, then cooled to between and C. The precipitateformed was isolated by filtration and was recrystallized from methanol.59.4 gm. of 3a-acetoxy-23,23- dimethoxy-24-nor-5 3-cholane was obtainedat a melting point of 133 to 134 C., and a specific rotation, [u] =+40.5(c.=0.5% in chloroform).

Analysis.--Calculated for C H O (molecular weight =434.64) (percent): C,74.61; H, 10.67. Found (percent): C, 74.3; H, 10.5.

Hydrolysis of the ketal: 50 gm. of the ketal obtained above was placedin suspension in 400 cc. of acetone containing 20% of water. Then cc. ofconcentrated hydrochloric acid was added. The suspension was heated toreflux [for a period of 30 minutes, then cooled to ambient temperature.400 cc. of water was added progressively to the suspension and thecrystals formed were isolated by filtration. 44 gm. of3a-acetoxy-23-oxo-24-nor-5fl-cholane were obtained, having a meltingpoint of 138 C. and a specific rotation [a] =|33 (c. =0.5% inchloroform).

Analysis.Calcnlated for C H O (molecular weight =388.57) (percent): C,77.27; H, 10.37. Found (percent): C, 77.0; H, 10.1.

Step B.The methyl ester of 3B-hydroxy-26,27-dinor-23-trans-5fi-cholest-23-en-25-oic acid: 6.7 gm. of sodium methylate and100 cc. of methanol were introduced into a balloon flask. Slowly, whileagitating at a temperature between 0 and +5 C., a solution of 26 gm. ofmethyl diethylphosphonoacetate in 50 cc. of methanol were added. Next 40gm. of 3a-acetoxy-23-oxo-24-nor-5p-cholane, then 100 cc. of methanolwere added progressively to the above solution. The mixture was agitatedfor a period of hours at about 0 C. Next, while maintaining the sametemperature, 500 cc. of iced water, then 10.6 cc. of concentratedhydrochloric acid were added, and the agitation was continued for onehour. The crystals formed were isolated by filtration and 41.4 gm. ofthe methyl ester of 3ot-hydroxy 26,27 diner-23-trans-5,B-cholest-23-en-25-oic acid were obtained having a melting point of 120 C., and aspecific rotation of [a] =+32.5 (c. =1% in chloroform).

Analysis.-Calculated for C H O (molecular weight =402.60) (percent): C,77.56; H, 10.52. Found (percent): C, 77.7; H, 10.4.

U.V. Spectra (ethanol): max. at 213 nm.

Etta; 7

The R.M.N. spectra establishes that the methoxycarbonyl grouping is in atrans position with reference to the methylene in the 22-position.

Step C.--The methyl ester of 3ot-hydroxy-26,'27-dinor-5,3-cholestan-25-oic acid: 4 gm. of the methyl ester of3u-hydroxy-'26,27-dinor-2S-trans-SB cholest-23-en-25-oic acid weredissolved in 60 cc. of methanol. 1 gm. of palladized talc (containing 2%of palladium) was added to the mixture, and a stream of hydrogen waspassed therethrough at ambient temperature for a period of 40 minutes.The catalyst was separated by filtration and the reaction mixture wasevaporated to dryness.

The residue was recrystallized from methanol. 4 gm. of the methyl esterof 3a-hydroxy-26,27-dinor-5fi-cholestan- 25-oic acid were obtainedhaving a melting point of 110 C., and a specific rotation [a] -=-|28.5(c.=l% in chloroform) Analysis.Calculated for C H O (molecular weight=404.7) (percent): C, 77.18; H, 10.96. Found (percent): C, 77.1; H,11.1.

Step D.The methyl ester of 3-oxo-26,27-dinor-5;8- chQIestan-ZS-Oic acid:40 gm. of the methyl ester of 3a- 1 6hydroxy-26,27-dinor-5p-cholestan-25-oic acid were introduced into 400cc. of acetone. An excess of a solution of chromic anhydride in aqueoussulfuric acid (Jones mixture) was added progressively to the solutionheld at 20 C.

The mixture was agitated for a period of a further hour, and then pouredinto water. 36 gm. of the methyl ester of3-oxo-26,27-dinor-SB-cholestan-ZS-oic acid were separated by filtration,having a melting point of 101 C., and a specific rotation of [a] =|-31.5(c.=l% in chloroform). I

Analysis.-Calculated for C H O (molecular weight -=402.6) (percent): C,77.56; H, 10.52; 0, 11.92. Found (percent): C, 77.2; H, 10.5; 0, 12.2.

Step E.The methyl ester of 3-oxo-4-bromo-26,27-dinor-5/3-cholestan-25-oic acid: 21 gm. of the methyl ester of3-oxo-26,27-dinor-5 3-cholestan-25-oic acid were placed in suspension in100 cc. of dimcthylformamide. The mixture was heated to 40 C. and onedrop of hydrobromic acid was added thereto. Then progressively 3 cc. ofbromine were added. Next 1 liter of a mixture of water and ice wereslowly added thereto. The precipitate formed was isolated by filtrationand 17 gm. of the methyl ester of3-oxo-4-bromo-26,27-dinor-5p-cholestan-25-oic acid were obtained havinga specific rotation of [a] =+43 (c.-= 1% in chloroform).

Analysis.Percent bromine: 16.6 (theoretical: 17.9).

The product was characterized by chromatography on a thin bed by Rf=0-63(support: silica gel, Kieselgel GF 254; eluant: benzene/ ethyl acetate7-3).

Step F.-The methyl ester of 3-oxo-26,27-dinorcholest- 4-en-25-0ic acid:cc. of dimethylformarnide, 16 gm. of lithium carbonate and 8 gm. oflithium bromide were introduced into a balloon flask while agitating.The mixture was heated to about C. after adding 16 gm. of the methylester of 3-oxo-4-bromo-26,27-dinor-5fi-cholestan-25-oic acid. Thereaction mixture was maintained for a period of 15 hours at the sametemperature. Next the reaction mixture was cooled to '+30 C. and pouredinto 800 cc. of a mixture of water and ice and 30 cc. of acetic acid.After 15 minutes of agitation the solid residue was separated bydecantation and dissolved in cc. of chloroform. The solution was washedwith water until the wash waters were neutral, and then evaporated todryness under vacuum. The residue was taken up with 250 cc. of methanol.The mixture was agitated for a period of 30 minutes at 0 C. and then byfiltration, 9 gm. of the methyl ester of 3-oxo-26,27-dinorcholest-4-en-25-oic acid were obtained having a melting point of C. and a specificrotation of [a] =+81 (c.=l% in chloroform).

Analysis.-Calculated for C H 0 (molecular weight '=400.5) (percent): C,78; H, 10.0. Found (percent): C, 77.9; H, 10.0.

U.V. Spectra (ethanol): max at 241 nm.

Step G.The methyl ester of 3-acetoxy-26,27-dinorcholesta-3,5-dien-25-oicacid: 6 gm. of the methyl ester of 3-oxo-26,27-dinorcholest-4-en-25 oicacid, 12 cc. of acetic anhydride and 6 cc. of acetyl chloride weremixed. The reaction mixture was heated to reflux for a period of 1 hour,then evaporated to dryness under vacuum. The residue was recrystallizedfrom isopropylether. 4.6 gm. of the methyl ester of3-acetoxy-26,27-dinorcholesta-3,5- dien-25-oic acid were obtained havinga melting point of 106 C. and a specific rotation of [a] =83.5 (c.=l% inchloroform).

The R.M.N. spectra is in accord with the structure indicated.

Step H.The methyl ester of 3/3-hydroxy-26,27-dinorcholest-5-en-25-oicacid: 4 gm. of the methyl ester of 3-acetoxy-26,27-dinorcholesta-3,S-dien-25-oic acid and 32 cc. oftetrahydrofuran were mixed. Next at 0 C., 8 cc. of methanol and 0.8 gm.of sodiumborohydride, then 4 cc. of water were introduced into themixture. Then, slowly and at the same temperature, 9.5 cc. of an aqueousnormal solution of sodium hydroxide were added. Then the mixture wasagitated for a period of 1 hour. The mixture was next acidified by theaddition of 4 cc. of acetic acid and 8 cc. of water. The methanol andthe tetrahydrofuran were distilled under reduced pressure whilemaintaining the volume of the mixture constant by the addition of water.The solid formed was separated by filtration. This solid was a mixtureof 3fi-hydroxy-ZG,27-dinorcholest-5 en-25-oic acid and its methyl ester.In order to convert the acid into the methyl ester, this mixture wasreacted with 40 cc. of methanol and 0.5 cc. of acetyl chloride for aperiod of 24 hours at room temperature, 1.2 gm. of the methyl ester of3fi-hydroxy-26,27-dinorcholest-5-en-25- oic acid was isolated byfiltration and washing with methanol. The R.M.N. spectra is in accordwith the structure indicated. This compound is described by Dauben, J.Am. Chem. Soc., 74, 559 (1952).

EXAMPLE H Preparation of the methyl ester of 3,8-hydroxy-26,27-dinorcholesta-5,7-dien-25-oic acid Step A.-The methyl ester of3-oxo-26,27-dinorcholesta-4,6-dien-25-oic acid: 20 gm. of the methylester of 3-acetoxy-26,27-dinorcholesta-3,5-dien-25-oic acid were placedin suspension in a mixture of 60 cc. of dimethylformamide and 1 cc. ofwater. The suspension was cooled to about C. and slowly, over a periodof 1 hour, 8.5 gm. of N-bromosuccinimide was added thereto whileagitating and maintaining the temperature between 0 and +2 C. Aprogressive dissolution of the product in suspension was observed and bythe end of the introduction of the reactant a partial precipitation ofthe methyl ester of 3-oxo-6;8-brom0-26,27-dinorcholest-4-en-25-olic acidwas observed.

The agitation was continued for a period of 15 minutes, then 10 gm. oflithium carbonate and 5 gm. of lithium bromide were added to thereaction medium. The suspension was agitated under an atmosphere ofnitrogen and heated over a period of 30 minutes to 95 to 100 C. Theagitation was continued at this temperature for a period of 3 hours.Then the reaction mixture was cooled to 20 to 25 C., then poured into amixture containing 250 cc. of water, 250 gm. of ice and 20 cc. of aceticacid. This mixture was agitated for a period of 1 hour. The precipitatewas separated by filtration, washed with water, and dried.

By recrystallization from ethyl acetate, 13.5 gm. of methyl ester of3-oxo-26,27-dinorcholesta-4,6-dien-25-oic acid was obtained having amelting point of 160 C.; and a specific rotation [a] =+28:1 (c.=1% inchloroform).

U.V. Spectra (ethanol): max.=285 nm. e=25.950.

Analysis.Calculated for C H O (molecular weight =398.56) (percent): C,78.4; H, 9.6. Found (percent): C, 78.2; H, 9.5.

Step B.The methyl ester of3-acetoxy-26,27-dinorcholesta-3,5,7-trien-25-oic acid: gm. of the methylester of 3-oxo-26,27-dinorcholesta-4,6-dien-25-oic acid were mixed with50 cc. of acetic anhydride, 8 cc. of pyridine and 25 cc. of acetylchloride. The mixture was heated at reflux for a period of 6 hours underan inert atmosphere and then evaporated to dryness. By successiverecrystallization of the residue from methanol, the methyl ester of3-acetoxy-Z6,27-dinorcholesta-3,5,7-trien-25-oic acid was obtained.

U.V. Spectra (ethanol): max.=301, 314 and 330 nm.

The product is immediately reduced according to the method described inthe following step.

Step C.-The methyl ester of3fi-hydroxy-26,27-dinorcholesta-5,7-dien-26-oic acid: 10 gm. of methylester of 3-acetoxy-26,27-dinorcholesta-3,5,7-trien-25-oic acid weremixed with 25 cc. of tetrahydrofuran, 25 cc. of water, 25 cc. ofmethanol and then 2.5 gm. of sodium borohydride.

The reaction mixture was agitated for a period of 16 hours at roomtemperature, then the solvents were eliminated by distillation underreduced pressure. A precipitate in water of the methyl ester of3fl-hydroxy-26,27-dinorcholesta-5,7-dien-25-oic acid, partiallysaponified, was obtained, which was converted completely into the methylester by the action of methanol in the presence of hydrochloric acid asa catalyst.

The product is characterized by the formation of its acetate. The methylester of 3fl-acetoxy-26,27-dinorcholesta-5,7-dien-25-oic acid wasobtained identical to the product described by Campbell et al.,Steroids, 13, page 574 (1969).

The preceding specific embodiments are illustrative of the pratice ofthe invention. It is to be understood, however, that other embodimentsknown to those skilled in the art or described herein may be employedwithout departing from the spirit of the invention or the scope of theappended claims.

We claim:

1. A process for the preparation of esters of 26,27-dinorcholestadien-ZS-oic acid of the formula COOR wherein R representsthe acyl of an organic carboxylic acid having 1 to 10 carbon atoms and Rrepresents lower alkyl, which consists essentially of the steps of (a)subjecting a compound of the formula wherein R represents the acyl of anorganic carboxylic acid having from 1 to 10 carbon atoms and Xrepresents a member selected from the group consisting of lower alkyl,cycloalkyl having 5 to 6 carbon atoms and phenyl, to the action of ozoneand thereafter to the action of a reducing agent,

(b) performing a Wittig reaction with a Wittig reactant selected fromthe group consisting of lower alkyl 0,0-dilower alkylphosphonoacettaeand an alkylidene phosphorane of the formula wherein R is lower alkyland Ar is phenyl on the resultant compound of the formula Rio-- whereinR has the above-assigned meaning,

(c) subjecting the resultant compound of the formula wherein R has theabove-assigned meaning by the action of an oxidizing agent capable ofoxidizing a hydroxy to a ketone,

(e) brominating the resultant compound of the formula COOR COOR

wherein R has the above-assigned meaning, by the action of amonobrominating agent, (if) reacting the resultant compound of theformula CODE wherein R has the above-assigned meaning, with adehydrobrominating agent, (g) reacting the resultant compound of theformula COOR O wherein R has the above-assigned meaning, with anacylating derivative of an organic carboxylic acid having 1 to carbonatoms, and

(h) recovering said esters of 26,27-dinorcholestadien- -oic acid.

2. The process of claim 1 wherein said reducing agent of step (a) iszinc in the presence of acetic acid.

3. The process of claim 1, step (d), wherein said oxidizing agentcapable of oxidizing a hydroxy to a ketone is selected from the groupconsisting of chromic anhydride, bromine in the presence of a buffer, anN-haloamide, a ketone in the presence of an aluminum alcoholate andcyclohexanone in the presence of Raney nickel.

4. The process of claim 1, step (e), wherein said monobrominating agentis selected from the group consisting of bromine, an alkali metalbromate, the hydrobromide of perbromopyridine and N-bromosuccinimide.

5. The process of claim 1, step (f), wherein said dehydrobrominatingagent is selected from the group consisting of a lithium halide in thepresence of a di-lower alkylamide of a lower alkanoic acid, heating inthe presence of a pyridine base, a semi-carbazide followed by anexchange reaction with a carbonylated derivative, a hydrazine followedby an exchange reaction with a carbonylated derivative, a loweralkylhydrazine followed by an exchanged reaction with a carbonylatedderivative, and a phenylhydrazine followed by an exchange reaction witha carbonylated derivative.

6. The process of claim 1, step (g), wherein said acylating derivativeis selected from the group consitsing of an acid anhydride of theformula (R CO) O and a mixture of said acid anhydride and thecorresponding acid chloride, where R has the above-assigned meaning.

7. The process of claim 1 wherein R is methyl.

8. The process of claim 1 wherein R is the acyl of an organic carboxylicacid having 1 to 10 carbon atoms selected from the group consisting ofalkanoic acids, cycloalkylcarboxylic acids, cycloalkylalkanoic acids,benzoic acid, alkylbenzoic acids, phenylalkanoic acids andalkylphenylalkanoic acids.

9. A process for the preparation of esters of 26,27-dinorcholesten-ZS-oic acids of the formula COOR HO- wherein R representslower alkyl, which consists essentially of the steps of reducing the 3,4double bond of a compound of the formula COOR R 0 wherein R representsthe acyl of an organic carboxylic acid having 1 to 10 carbon atoms and Rrepresents lower alkyl, by the action of a mixed hydride selected fromthe group consisting of alkali metal borohydride, aluminum lithiumhydride, and lithium tri-tert.-butoxyaluminum hydride and recoveringsaid esters of 26,27-dinorcholesten- 25-0ic acids.

10. A process for the preparation of esters of 26,27-dinorcholestadien-ZS-oic acids of the formula COOR HO wherein Rrepresents the acyl of an organic carboxylic acid having 1 to 10 carbonatoms and R represents lower alkyl to the action of a monobrominatingagent,

(b) reacting the resultant compound of the formula wherein R has theabove-assigned meaning, with a dehydrobrominating agent, (0) reactingthe resultant compound of the formula wherein R has the above assignedmeaning, with an 4Q acylating derivative of an organic carboxylic acidhaving 1 to 10 carbon atoms, v (d) reducing the 3,4 double bond of theresultant compound having the formula C O 0 B wherein R and R have theabove-assigned meanings, by the action of a mixed hydride, and

(e) recovering said esters of 26,27-dinorcholestadien- 25-oic acids.

11. The process of claim 10, step (a), wherein said monobrominatingagent is selected from the group consisting of bromine, an alkali metalbromate, the hydrobromide of perbromopyridine and N-bromosuccinimide.

'12. The process of claim 10, step (1:), wherein said dehydrobrominatingagent is selected from the group consisting of a lithium halide in thepresence of a di-lower alkylamide of a lower alkanoic acid, heating inthe presence of a pyridine base, a semi-carbazide followed by anexchange reaction with a carbonylated derivative, a hydrazine followedby an exchange reaction with a carbonylated derivative, a loweralkylhydrazine followed by an exchange reaction with a carbonylatedderivative, and a phenylhydrazine followed by an exchange reaction witha carbonylated derivative.

13. The process of claim 10, step (c), wherein said acylating derivativeis selected from the group consisting 22' mixture of said acid anhydrideand the corresponding acid chloride, where R; has the above-assignedmeaning.

14. The process of claim 10, step (d), wherein said mixed hydride isselected from the group consisting of alkali metal borohydride, aluminumlithium hydride, and lithium tri-tert.-butoxyaluminum hydride.

15. A compound of the formula wherein R is a member selected from thegroup consisting of hydrogen and the acyl of an organic carboxylic acidhaving 1 to 10 carbon atoms and R is a member selected from the groupconsisting of hydrogen and lower alkyl.

16. A compound of the formula wherein R is lower alkyl, X is a 55hydrogen and X is bromine.

17. A compound of the formula wherein R is lower alkyl and A is a doublebond.

18. A compound of the formula wherein R is lower alkyl, R; is the acylof an organic carboxylic acid having 1 to 10 carbon atoms and A is amember selected from the group consisting of two hydrogens and a doublebond.

19. A compound of the formula COOR of an acid anhydride of the formula(R CO) O and a wherein R is lower alkyl.

2'4 20. A compound of the formula 7 subjecting the latter to abromination reaction and then a dehydrobromination reaction to obtain acompound of the formula wherein R is lower alkyl. 10

21. A process for the preparation of a compound of 003 the formula 0 Areacting the latter with an acylation agent to obtain a compound of theformula A I 00R wherein R is lower alkyl and A may be 2 hydrogens or adouble bond comprising reacting a compound of the formula 0 0R wherein Ris the acyl of an organic carboxylic acid of 1 E0" to 10 carbon atomsand reducing the latter with a mixed hydride selected from the groupconsisting of alkali metal bo'rohydride, aluminum lithium hydride andlithium tri- Whefeln R 13 lower alkyl Wlth all OXldlZlng agent p bte'rt.butoxy aluminum hydride to obtain the desired comof oxidizing ahydroxy to a ketone to obtain a compound d, of the formula ReferencesCited UNITED STATES PATENTS 3,560,558 2/1971 Hayakawa et al. 260514ELBERT ROBERTS, Primary Examiner US. 01. X.R. 260-397.2

m3? v UNITED STA'IES PATBENT 0mm;

- @ERTIFICATE OF CORRECTXON I Page 1 of 2 Pitent No. 8ol6o7 D t d P 97Invencorfif BERNARD GOFFINEI It iseertified thac error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

EN THBPATENT IN. THE APPLICATION -Cc 'l. Line- Page Line 2 2o 3CR"iiFiCATE or 0 :REQTION Fateut Ho Invcatorm} BQHKMKD GQFFlNEEl It incertified that error appears in the ebovwridentifiad pa and Chlt saidLetters Patent are hereby corrected an shown below:

-- Ar P cncoon Signed 3 nd sealed this 1st day of October 1974,

